GLWidget for OpenTk

GLWidget.cs

//https://github.com/Nihlus/GLWidgetTest/blob/master/GLWidget/GLWidgetGTK3/GLWidget.cs
#region License
//
// The Open Toolkit Library License
//
// Copyright (c) 2006 - 2009 the Open Toolkit library, except where noted.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights to
// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
// the Software, and to permit persons to whom the Software is furnished to do
// so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
// OTHER DEALINGS IN THE SOFTWARE.
//
#endregion

using System;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using System.Security;
using System.Threading;
using System.ComponentModel;


using OpenTK.Graphics;
using OpenTK.Platform;

using Gtk;

namespace OpenTK
{
	[ToolboxItem(true)]
	public class GLWidget : DrawingArea
	{

		#region Static attrs.

		private static int _graphicsContextCount;
		private static bool _sharedContextInitialized;

		public bool IsRenderHandler { get; set; } = false;

		#endregion

		#region Attributes

		private IGraphicsContext _graphicsContext;
		private IWindowInfo _windowInfo;
		private bool _initialized;

		#endregion

		#region Properties

		/// <summary>Use a single buffer versus a double buffer.</summary>
		[Browsable(true)]
		public bool SingleBuffer { get; set; }

		/// <summary>Color Buffer Bits-Per-Pixel</summary>
		public int ColorBPP { get; set; }

		/// <summary>Accumulation Buffer Bits-Per-Pixel</summary>
		public int AccumulatorBPP { get; set; }

		/// <summary>Depth Buffer Bits-Per-Pixel</summary>
		public int DepthBPP { get; set; }

		/// <summary>Stencil Buffer Bits-Per-Pixel</summary>
		public int StencilBPP { get; set; }

		/// <summary>Number of samples</summary>
		public int Samples { get; set; }

		/// <summary>Indicates if steropic renderering is enabled</summary>
		public bool Stereo { get; set; }

		/// <summary>The major version of OpenGL to use.</summary>
		public int GLVersionMajor { get; set; }

		/// <summary>The minor version of OpenGL to use.</summary>
		public int GLVersionMinor { get; set; }

		public GraphicsContextFlags GraphicsContextFlags
		{
			get;
			set;
		}

		#endregion

		#region Construction/Destruction

		/// <summary>Constructs a new GLWidget.</summary>
		public GLWidget()
			: this(GraphicsMode.Default)
		{
		}

		/// <summary>Constructs a new GLWidget using a given GraphicsMode</summary>
		public GLWidget(GraphicsMode graphicsMode)
			: this(graphicsMode, 1, 0, GraphicsContextFlags.Default)
		{
		}

		/// <summary>Constructs a new GLWidget</summary>
		public GLWidget(GraphicsMode graphicsMode, int glVersionMajor, int glVersionMinor, GraphicsContextFlags graphicsContextFlags)
		{
			SingleBuffer = graphicsMode.Buffers == 1;
			ColorBPP = graphicsMode.ColorFormat.BitsPerPixel;
			AccumulatorBPP = graphicsMode.AccumulatorFormat.BitsPerPixel;
			DepthBPP = graphicsMode.Depth;
			StencilBPP = graphicsMode.Stencil;
			Samples = graphicsMode.Samples;
			Stereo = graphicsMode.Stereo;

			GLVersionMajor = glVersionMajor;
			GLVersionMinor = glVersionMinor;
			GraphicsContextFlags = graphicsContextFlags;
		}

		~GLWidget()
		{
			Dispose(false);
		}
		
		protected override void Dispose(bool disposing)
		{
			if (disposing)
			{
				try
				{
					GraphicsContext.MakeCurrent(WindowInfo);
				}catch(Exception ex)
				{

				}

				OnShuttingDown();
				
				if (OpenTK.Graphics.GraphicsContext.ShareContexts && (Interlocked.Decrement(ref _graphicsContextCount) == 0))
				{
					OnGraphicsContextShuttingDown();
					_sharedContextInitialized = false;
				}
				
				GraphicsContext.Dispose();
			}
		}

		#endregion

		#region New Events

		// Called when the first GraphicsContext is created in the case of GraphicsContext.ShareContexts == True;
		public static event EventHandler GraphicsContextInitialized;

		private static void OnGraphicsContextInitialized()
		{
			if (GraphicsContextInitialized != null)
			{
				GraphicsContextInitialized(null, EventArgs.Empty);
			}
		}

		// Called when the first GraphicsContext is being destroyed in the case of GraphicsContext.ShareContexts == True;
		public static event EventHandler GraphicsContextShuttingDown;

		private static void OnGraphicsContextShuttingDown()
		{
			if (GraphicsContextShuttingDown != null)
			{
				GraphicsContextShuttingDown(null, EventArgs.Empty);
			}
		}

		// Called when this GLWidget has a valid GraphicsContext
		public event EventHandler Initialized;

		protected virtual void OnInitialized()
		{
			if (Initialized != null)
			{
				Initialized(this, EventArgs.Empty);
			}
		}

		// Called when this GLWidget needs to render a frame
		public event EventHandler RenderFrame;

		protected virtual void OnRenderFrame()
		{
			if (RenderFrame != null)
			{
				RenderFrame(this, EventArgs.Empty);
			}
		}

		// Called when this GLWidget is being Disposed
		public event EventHandler ShuttingDown;

		protected virtual void OnShuttingDown()
		{
			if (ShuttingDown != null)
			{
				ShuttingDown(this, EventArgs.Empty);
			}
		}

		#endregion

		// Called when a widget is realized. (window handles and such are valid)
		// protected override void OnRealized() { base.OnRealized(); }

		// Called when the widget needs to be (fully or partially) redrawn.

		protected override bool OnDrawn(Cairo.Context cr)
		{
			if (!_initialized)
				Initialize();
			else if(!IsRenderHandler)
				GraphicsContext.MakeCurrent(WindowInfo);

			return true;
		}

		// Called on Resize
		protected override bool OnConfigureEvent(Gdk.EventConfigure evnt)
		{
			if (GraphicsContext != null)
			{
				GraphicsContext.Update(WindowInfo);
			}

			return true;
		}

		private void Initialize()
		{
			_initialized = true;

			// If this looks uninitialized...  initialize.
			if (ColorBPP == 0)
			{
				ColorBPP = 32;

				if (DepthBPP == 0)
				{
					DepthBPP = 16;
				}
			}

			ColorFormat colorBufferColorFormat = new ColorFormat(ColorBPP);

			ColorFormat accumulationColorFormat = new ColorFormat(AccumulatorBPP);

			int buffers = 2;
			if (SingleBuffer)
			{
				buffers--;
			}

			GraphicsMode graphicsMode = new GraphicsMode(colorBufferColorFormat, DepthBPP, StencilBPP, Samples, accumulationColorFormat, buffers, Stereo);

			if (OpenTK.Configuration.RunningOnWindows)
			{
				Console.WriteLine("OpenTK running on windows");
			}
			else if (OpenTK.Configuration.RunningOnMacOS)
			{
				Console.WriteLine("OpenTK running on OSX");
			}
			else
			{
				Console.WriteLine("OpenTK running on X11");
			}

			this.Window.EnsureNative();

			// IWindowInfo
			if (OpenTK.Configuration.RunningOnWindows)
			{
				WindowInfo = InitializeWindows();
			}
			else if (OpenTK.Configuration.RunningOnMacOS)
			{
				WindowInfo = InitializeOSX();
			}
			else
			{
				WindowInfo = InitializeX(graphicsMode);
			}

			// GraphicsContext
			GraphicsContext = new GraphicsContext(graphicsMode, WindowInfo, GLVersionMajor, GLVersionMinor, GraphicsContextFlags);
			GraphicsContext.MakeCurrent(WindowInfo);

			if (OpenTK.Graphics.GraphicsContext.ShareContexts)
			{
				Interlocked.Increment(ref _graphicsContextCount);

				if (!_sharedContextInitialized)
				{
					_sharedContextInitialized = true;
					((IGraphicsContextInternal)GraphicsContext).LoadAll();
					OnGraphicsContextInitialized();
				}
			}
			else
			{
				((IGraphicsContextInternal)GraphicsContext).LoadAll();
				OnGraphicsContextInitialized();
			}

			OnInitialized();
		}

		#region Windows Specific initalization

		IWindowInfo InitializeWindows()
		{
			IntPtr windowHandle = gdk_win32_window_get_handle(this.Window.Handle);
			return Utilities.CreateWindowsWindowInfo(windowHandle);
		}

		[SuppressUnmanagedCodeSecurity, DllImport("libgdk-3-0.dll")]
		public static extern IntPtr gdk_win32_window_get_handle(IntPtr d);

		#endregion

		#region OSX Specific Initialization

		IWindowInfo InitializeOSX()
		{
			IntPtr windowHandle = gdk_quartz_window_get_nswindow(this.Window.Handle);
			//IntPtr viewHandle = gdk_quartz_window_get_nsview(this.GdkWindow.Handle);
			return Utilities.CreateMacOSCarbonWindowInfo(windowHandle, true, true);
		}

		[SuppressUnmanagedCodeSecurity, DllImport("libgdk-quartz-2.0.0.dylib")]
		static extern IntPtr gdk_quartz_window_get_nswindow(IntPtr handle);

		[SuppressUnmanagedCodeSecurity, DllImport("libgdk-quartz-2.0.0.dylib")]
		static extern IntPtr gdk_quartz_window_get_nsview(IntPtr handle);

		#endregion

		#region X Specific Initialization

		const string UnixLibGdkName = "libgdk-3.so.0";

		const string UnixLibX11Name = "libX11.so.6";
		const string UnixLibGLName = "libGL.so.1";

		const int GLX_NONE = 0;
		const int GLX_USE_GL = 1;
		const int GLX_BUFFER_SIZE = 2;
		const int GLX_LEVEL = 3;
		const int GLX_RGBA = 4;
		const int GLX_DOUBLEBUFFER = 5;
		const int GLX_STEREO = 6;
		const int GLX_AUX_BUFFERS = 7;
		const int GLX_RED_SIZE = 8;
		const int GLX_GREEN_SIZE = 9;
		const int GLX_BLUE_SIZE = 10;
		const int GLX_ALPHA_SIZE = 11;
		const int GLX_DEPTH_SIZE = 12;
		const int GLX_STENCIL_SIZE = 13;
		const int GLX_ACCUM_RED_SIZE = 14;
		const int GLX_ACCUM_GREEN_SIZE = 15;
		const int GLX_ACCUM_BLUE_SIZE = 16;
		const int GLX_ACCUM_ALPHA_SIZE = 17;

		public enum XVisualClass
		{
			StaticGray = 0,
			GrayScale = 1,
			StaticColor = 2,
			PseudoColor = 3,
			TrueColor = 4,
			DirectColor = 5,
		}

		[StructLayout(LayoutKind.Sequential)]
		struct XVisualInfo
		{
			public IntPtr Visual;
			public IntPtr VisualID;
			public int Screen;
			public int Depth;
			public XVisualClass Class;
			public long RedMask;
			public long GreenMask;
			public long blueMask;
			public int ColormapSize;
			public int BitsPerRgb;

			public override string ToString()
			{
				return $"id ({VisualID}), screen ({Screen}), depth ({Depth}), class ({Class})";
			}
		}

		[Flags]
		internal enum XVisualInfoMask
		{
			No = 0x0,
			ID = 0x1,
			Screen = 0x2,
			Depth = 0x4,
			Class = 0x8,
			Red = 0x10,
			Green = 0x20,
			Blue = 0x40,
			ColormapSize = 0x80,
			BitsPerRGB = 0x100,
			All = 0x1FF,
		}

		private IWindowInfo InitializeX(GraphicsMode mode)
		{
			IntPtr display = gdk_x11_display_get_xdisplay(Display.Handle);
			int screen = Screen.Number;

			IntPtr windowHandle = gdk_x11_window_get_xid(Window.Handle);
			IntPtr rootWindow   = gdk_x11_window_get_xid(RootWindow.Handle);

			IntPtr visualInfo;

			if (mode.Index.HasValue)
			{
				XVisualInfo info = new XVisualInfo();
				info.VisualID = mode.Index.Value;
				int dummy;
				visualInfo = XGetVisualInfo(display, XVisualInfoMask.ID, ref info, out dummy);
			}
			else
			{
				visualInfo = GetVisualInfo(display);
			}

			IWindowInfo retval = Utilities.CreateX11WindowInfo(display, screen, windowHandle, rootWindow, visualInfo);
			XFree(visualInfo);

			return retval;
		}

		private static IntPtr XGetVisualInfo(IntPtr display, XVisualInfoMask vinfo_mask, ref XVisualInfo template, out int nitems)
		{
			return XGetVisualInfoInternal(display, (IntPtr)(int)vinfo_mask, ref template, out nitems);
		}

		private IntPtr GetVisualInfo(IntPtr display)
		{
			try
			{
				int[] attributes = AttributeList.ToArray();
				return glXChooseVisual(display, Screen.Number, attributes);
			}
			catch (DllNotFoundException e)
			{
				throw new DllNotFoundException("OpenGL dll not found!", e);
			}
			catch (EntryPointNotFoundException enf)
			{
				throw new EntryPointNotFoundException("Glx entry point not found!", enf);
			}
		}

		private List<int> AttributeList
		{
			get
			{
				List<int> attributeList = new List<int>(24);

				attributeList.Add(GLX_RGBA);

				if (!SingleBuffer)
					attributeList.Add(GLX_DOUBLEBUFFER);

				if (Stereo)
					attributeList.Add(GLX_STEREO);

				attributeList.Add(GLX_RED_SIZE);
				attributeList.Add(ColorBPP / 4); // TODO support 16-bit

				attributeList.Add(GLX_GREEN_SIZE);
				attributeList.Add(ColorBPP / 4); // TODO support 16-bit

				attributeList.Add(GLX_BLUE_SIZE);
				attributeList.Add(ColorBPP / 4); // TODO support 16-bit

				attributeList.Add(GLX_ALPHA_SIZE);
				attributeList.Add(ColorBPP / 4); // TODO support 16-bit

				attributeList.Add(GLX_DEPTH_SIZE);
				attributeList.Add(DepthBPP);

				attributeList.Add(GLX_STENCIL_SIZE);
				attributeList.Add(StencilBPP);

				attributeList.Add(GLX_ACCUM_RED_SIZE);
				attributeList.Add(AccumulatorBPP / 4);// TODO support 16-bit

				attributeList.Add(GLX_ACCUM_GREEN_SIZE);
				attributeList.Add(AccumulatorBPP / 4);// TODO support 16-bit

				attributeList.Add(GLX_ACCUM_BLUE_SIZE);
				attributeList.Add(AccumulatorBPP / 4);// TODO support 16-bit

				attributeList.Add(GLX_ACCUM_ALPHA_SIZE);
				attributeList.Add(AccumulatorBPP / 4);// TODO support 16-bit

				attributeList.Add(GLX_NONE);

				return attributeList;
			}
		}

		public IGraphicsContext GraphicsContext { get => _graphicsContext; set => _graphicsContext = value; }
		public IWindowInfo WindowInfo { get => _windowInfo; set => _windowInfo = value; }

		[DllImport(UnixLibX11Name, EntryPoint = "XGetVisualInfo")]
		private static extern IntPtr XGetVisualInfoInternal(IntPtr display, IntPtr vinfo_mask, ref XVisualInfo template, out int nitems);

		[SuppressUnmanagedCodeSecurity, DllImport(UnixLibX11Name)]
		private static extern void XFree(IntPtr handle);

		/// <summary> Returns the X resource (window or pixmap) belonging to a GdkDrawable. </summary>
		/// <remarks> XID gdk_x11_drawable_get_xid(GdkDrawable *drawable); </remarks>
		/// <param name="gdkDisplay"> The GdkDrawable. </param>
		/// <returns> The ID of drawable's X resource. </returns>
		[SuppressUnmanagedCodeSecurity, DllImport(UnixLibGdkName)]
		private static extern IntPtr gdk_x11_drawable_get_xid(IntPtr gdkDisplay);

		/// <summary> Returns the X resource (window or pixmap) belonging to a GdkDrawable. </summary>
		/// <remarks> XID gdk_x11_drawable_get_xid(GdkDrawable *drawable); </remarks>
		/// <param name="gdkDisplay"> The GdkDrawable. </param>
		/// <returns> The ID of drawable's X resource. </returns>
		[SuppressUnmanagedCodeSecurity, DllImport(UnixLibGdkName)]
		private static extern IntPtr gdk_x11_window_get_xid(IntPtr gdkDisplay);

		/// <summary> Returns the X display of a GdkDisplay. </summary>
		/// <remarks> Display* gdk_x11_display_get_xdisplay(GdkDisplay *display); </remarks>
		/// <param name="gdkDisplay"> The GdkDrawable. </param>
		/// <returns> The X Display of the GdkDisplay. </returns>
		[SuppressUnmanagedCodeSecurity, DllImport(UnixLibGdkName)]
		private static extern IntPtr gdk_x11_display_get_xdisplay(IntPtr gdkDisplay);

		[SuppressUnmanagedCodeSecurity, DllImport(UnixLibGLName)]
		private static extern IntPtr glXChooseVisual(IntPtr display, int screen, int[] attr);

		#endregion
	}
}